Fan assembly



June 18, 1963 n Filed June 125, 1959 Inni R. L. HULL ETAL FAN ASSEMBLY I/Z'LA 2 Sheets-Sheet 1 j /zo zYl cHARD L. H Ul-l- Raam,

www, ATTORNEYS` FAN ASSEMBLY Filed June 25, 1959 2 Sheets-Shag?. 2

ATTORNEYS United States Patent O 3,094,273 FAN ASSEMBLY Richard L. Hull, Davenport, Iowa, and Alonzo M. Harp, Moline, Ill., assign'ors to Ametek, Inc., a corporation of Delaware Filed June 25, 1959, Ser. No. 822,951 7 Claims. (Cl. 230-211) This invention relates to a fan assembly, and particularly to a fan assembly for moving hot gases wherein means are provided for cooling one of the bearings of the assembly.

In high temperature ovens or furnaces where the hot gases in the furnace 'are moved therethrough by a fan assembly, it has been found that certain of the parts of the yfan assembly will not withstand the high temperature too well. This is particularly rtrue of the bearings which rotatably support the fan wheel shaft. Various arrangements have been devised which segregate certain portions of the fan assembly, including the bearings, from the hot gases passing through the furnace. Such arrangements are not entirely satisfactory for certain types of fan assemblies, since the parts close to the hi-gh temperature furnace are subjected to high temperatures even though they are segregated from the interior of the oven or furnace.

It is an object of this invention to provide a fan assembly for moving hot `gases wherein the bearings for the fan wheel shaft are segregated from the hot gases being moved.

type of fan assembly including a frame member supported on a shroud ring and a vane arr-angement connected to the shaft for deflecting the cooling air passed through the bearing means by the auxiliary fan.

In one aspect of the invention, the fan assembly for moving the hot gases has a fan wheel, a rotatable shaft connected to the fan wheel having a portion segregated from the hot gases, and tube or passage means surrounding part of the segregated portion of the shaft. In order to prevent the undue heating of the bearing means by the hot gases, a heat resistant frame member is located between one end of the tube and the hot gases. Interposed between this end of the tube and the frame member and connected to the shaft for rotation therewith is a rotating member. The cool gases pass through the bearing means and move against the rotating means which cause the gases to move outwardly away from the tube.

In a further aspect of the invention the rotating means includes Vanes mounted to form a centrifugal fan wheel. The frame member is supported by a plurality of rods secured to the shroud ring.

These and other objects, advantages and features of the invention will become apparent from the following description and drawings which are merely exemplary.

In the drawings:V

FIG. 1 is a cross-sectional side elevation of one embodiment of the fan assembly of the invention; and

FIG. 2 is a cross-sectional side elevation of another Vmember 1'2 by means of a plurality of rods 414. The

rods 14 are connected at one end to the shroud ring 10 and at the other end to the frame member l12. Frame member :1.2 substantially closes an opening in top .wall 13 to thereby insulate the air above the frame member ice from the very high temperatures of the interior 16 of the furnace. Vanes 10A may be located above the fan wheel 15.

In the form shown in FIG. l, the fan wheel 15 is rotated in a direction so as to move hot gases through the interior y16 of the furnace. Fan wheel 1S is secured to shaft `17 for rotation therewith. Shaft 17 itself is rotatably mounted in a pair of bearings 18 yand 19. In order to prevent the excessive heating of the portion of shaft 17 below frame member 12, a heat insulating tubular casing 20 is provided.

Shaft 17 may be suitably rotated, as shown in FIG. l, by motor 21 through the pulley and sheave arrangement shown generally as 22 in the drawing. Surrounding the portion of yshaft 17 above frame member 12 is a tube or passage means 23 held in position relative to the top wall of the furnace by plates 24, only one of which is shown, which are connected to a ring '25 bolted or otherwise secured to the top Wall '13, said plates having flanges 25A. In the FIG. l form, passage means y23 supports bearings -18 and 19 and has spaced openings 26 at its upper end. In order to move cool gases from the openings 26 through bearing 18, which is the bearing closest to the furnace and, therefore, the bearing which is subjected to the most heat, an auxiliary fan wheel 27 secured lto shaft '17 for rotation therewith may be provided. As can lbe seen in FIG. l, the cool gases will be moved by fan 'wheel 27 downwardly through tube 23v and then through bearing 18. However, it has been found that these gases hit the top of frame member 12. In order to alleviate this problem, a centrifugal fan wheel 2S having a plurality of spaced Vanes 29 thereon is mounted between 'the top of frame member 12 and the bottom of tube 23 on shaft 117 for rotation therewith. Thus, the gases which have been moved through bearing 18 by auxiliary fan wheel 27 are forced upwardly and outwardly in the direction `of the arrows with the assistance of the rotating rVanes 29. Wheel '2S also helps to prevent any leakage of the hot gases upwardly from the interior of the furnace to bearing 18.

If desired, lubricating passages 30 and 31 may be provided in bearings 18 and 19 respectively. Motor 21 may be secured to tube or passage means 23 by plate 32.

As can best be seen in FIG. l, the entire fan assembly may be removed from the furnace, as a unit, by merely loosening the connections bet-Ween top wall -13` of the furnace Iand ring 25. The assembly is adequately suppor-ted in position relative to the furnace by the flanges on frame 10, ring 25, plates 24, plate 32 and rods 14.

The modification of the invention illustrated in FIG. 2 operates in essentially the same manner as that shown in FIG. l, andsimilar parts have been given the same reference numeral with the addition of a B thereto. Y

In the FIG. 2 modification, the tube or passage means 23B is cup-shaped rather than cylindrical and the auxiliary fan 27 is omitted. In this case, the cool air ows inwardly and downwardly over the top surface of passage means 23B adjacent bearing 18B and against wheel 28B which forces it upwardly and outwardly in the direction of the arrows. Thus, the FIG. 2 modification operates in the same manner as that shown in FIG. l to cool the lower bearing.

Shaft 17A can be made up of `a plain shaft 35' bored at one end. A shaft 37 is then pressed part way into bore `36 and welded leaving a hollow yspace 38 below the lower bearing. Heat traveling up the solid portion of shaft 37 will be forced to the peripheral portion `of shaft 35 around bore 38, thus increasing the total heat transfer therefrom and further retarding the heating of the lower bearing. This feature can, of course, be applied to both modifications shown.

In order to further ensure heat dissipation, a hollow 3 housing 39 may be provided `which surrounds shaft 35. Water or other cooling liquid may be circulated through the hollow portion of housing 39 to provide cooling even Kben `the fan is inoperative and the oven or furnace is Since the normal action of fan wheel 28B is to draw some of the hot `gases from the blade upwardly through the center of casing (FIG. 2), a lower auxiliary fan wheel 35 may be lprovided on shaft `17A to act as a rotary seal to help prevent the leakage of hot air upwardly from the furnace toward lthe segregated portion of the shaft. If desired, this feature could also be incorporated in the FIG. 1 modification.

As can readily tbe seen, the fan assembly of the invention is especially useful in connection with high temperature ovens or furnaces or other applications where the parts of the assembly are subjected to the effect of gases at very high temperature. This utility is especially true in the case of the bearing adjacent the hot gases, which is adequately protected at all times by the combination of the frame member and the deecting vane arrangement of the invention, as well as by the heat dissipating construction of `the drive shaft and the auxiliary cooling jacket.

It will be understood that details of the construction can be varied without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

1. Apparatus comprising in combination, an enclosure within which gases are adapted to be heated to a high temperature, said enclosure including a wall having an outlet therein for the escape of hot gases from said enclosure; a fan assembly including first fan means located within said outlet for moving said gases in said enclosure; a drive shaft for said first fan means having a portion extending `transversely across said enclosure; spaced bearings for rotatably supporting said shaft, at least one of said bearings being adjacent said enclosure; insulating means extending transversely across said enclosure and completely surrounding and isolating from the enclosure, said portion of said drive shaft therein as well as said one of said lbearings; said insulating means having a recessed por-tion at one end thereof, second fan means 1ocated on said shaft between said one of said bearings and said insulating means for circulating cool gases over said one of said bearings said second fan means and said one of said bearings being positioned within said recessed of said bearings being located within said tubular means portion of said insulating means; and means for rotating said shaft.

2. Apparatus comprising in combination, an enclosure within which gases are adapted to be heated to a high temperature, said enclosure including a wall having an outle-t therein for the escape of hot gases from said enclosure; a fan assembly including first fan means located within said outlet for moving said gases in said enclosure; a d rive shaft for said first fan means having a first portion extending transversely across said enclosure, and a second portion extending outwardly from said enclosure; tubular means having openings near both ends thereof and surrounding said second portion of said shaft; bearings supported by said rtubular means for said shaft, at least one of said bearings being located within said tubular means adjacent said enclosure; insulating means extending transversely across said enclosure and completely surrounding and isolating from said enclosure, said first portion of said drive shaft as well as said oneof said bearings; second fan means for circulating cool gases through said tubular means and over the bearing therein; and means outside of said enclosure for rotating said shaft.

3. Apparatus comprising in combination, an enclosure within which gases are adapted to be heated to a high temperature, said enclosure including a wall having an outlet therein for the escape of hot gases from said enclosure; a

fan assembly including first fan means located within said outlet for moving said gases in said enclosure; a drive shaft for said first fan means having a first portion extending transversely across said enclosure, and a second portion extending outwardly from said enclosure; tubular means having openings near both ends thereof and surrounding said second portion of said shaft; bearings supported by said tubular means for said shaft, at least one of said bearings being located within said .tubular means `adjacent said enclosure; insulating means extending transversely across said enclosure and completely surrounding and isolating from said enclosure, said first portion of said `drive shaft as well as said one of said bearings; centrifugal fan means for circulating cool gases through said tubular means and over the bearing therein; and means outside of said enclosure for rotating said shaft.

4. Apparatus as claimed in claim l, in which a third fan means is provided between said insulating means and said first fan means for preventing hot gases from said enclosure from leaking into said insulating means around said shaft adjacent said first fan means.

5. A fan assembly for moving hot gases as claimed in claim 1, in which a hollow jacket surrounds said drive shaft and is located between said one of said bearings and said second fan means; and means for circulating cooling uid through said jacket.

6. A fan assembly for moving hot gases as claimed in claim 1, in which said drive shaft includes two parts, one of said parts being provided with an axial bore within at least one end thereof, and means connecting the two parts together at the end including said axial bore, whereby a chamber is formed within said drive shaft between said two parts.

7. Apparatus comprising in combination, an enclosure within which gases are adapted to be heated to a high temperature, said enclosure including a wall having an outlet therein for the escape of hot gases from said enclosure; a fan assembly including first fan means located within said outlet for moving said gases in said enclosure; a drive shaft for said first fan means having a first portion extending transversely across said enclosure, and a second portion extending outwardly from said enclosure; tubular means having openings near both ends thereof and surrounding said second portion of said shaft; bearings supported by said tubular means for said shaft, at least one adjacent said enclosure; insulating means extending transversely across said enclosure and completely surrounding and isolating from said enclosure, said first portion of said drive shaft as well as said one of said bearings; second fan means connected to said shaft and located between said one of said bearings and said first fan means; third fan means connected to said yshaft and located within said tubular means; and means outside of said enclosure for rotating said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 722,875 Naef Mar. 17, 1903 1,530,982 Coppus Mar. 24, 1925 1,953,540 Ogden Apr. 3, 1934 2,226,986 Wechsberg et al Dec. 31, 1940 2,352,206 Kendall June 27, 1944 2,656,973 Sutherland Oct. 27, 1953 2,694,157 Cone Nov. 9, 1954 2,697,179 Wendel Dec. 14, 1954 2,735,027 Formhals et al. Feb. 14, 1956 2,770,891 Wendel Nov. 20, 1956 FOREIGN PATENTS 346,140 Italy Jan. 30, 1937 388,991 France June 15, 1908 404,162 Great Britain Feb. 28, 1933 

3. APPARATUS COMPRISING IN COMBINATION, AN ENCLOSURE WITHIN WHICH GASES ARE ADAPTED TO BE HEATED TO A HIGH TEMPERATURE, SAID ENCLOSURE INCLUDING A WALL HAVING AN OUTLET THEREIN FOR THE ESCAPE OF HOT GASES FROM SAID ENCLOSURE; A FAN ASSEMBLY INCLUDING FIRST FAN MEANS LOCATED WITHIN SAID OUTLET FOR MOVING SAID GASES IN SAID ENCLOSURE; A DRIVE SHAFT FOR SAID FIRST FAN MEANS HAVING A FIRST PORTION EXTENDING TRANSVERSELY ACROSS SAID ENCLOSURE, AND A SECOND PORTION EXTENDING OUTWARDLY FROM SAID ENCLOSURE; TUBULAR MEANS HAVING OPENINGS NEAR BOTH ENDS THEREOF AND SURROUNDING SAID SECOND PORTION OF SAID SHAFT; BEARINGS SUPPORTED BY SAID TUBULAR MEANS FOR SAID SHAFT, AT LEAST ONE OF SAID BEARINGS BEING LOCATED WITHIN SAID TUBULAR MEANS ADJACENT SAID ENCLOSURE; INSULATING MEANS EXTENDING TRANSVERSELY ACROSS SAID ENCLOSURE AND COMPLETELY SURROUNDING AND ISOLATING FROM SAID ENCLOSURE, SAID FIRST PORTION OF SAID DRIVE SHAFT AS WELL AS SAID ONE OF SAID BEARINGS; CENTRIFUGAL FAN MEANS FOR CIRCULATING COOL GASES THROUGH SAID TUBULAR MEANS AND OVER THE BEARING THEREIN; AND MEANS OUTSIDE OF SAID ENCLOSURE FOR ROTATING SAID SHAFT. 